Genetic Variability and Correlation in Single Cross Hybrids of Quality Protein Maize ( Zea Mays   L.)

Genetic variability and correlation were studied in 36 maize genotypes (15 single cross hybrids, 9 parents and 12 checks), with 26 quality protein maize genotypes among them. They were evaluated at Samaru, Northern Guinea Savanna Zone of Nigeria for two years, 2005 and 2006. The experimental design used was partial lattice design with three replications. Analysis of variance revealed significant differences for all the traits observed. Highest grain yield of 9.5t/ha was obtained from the hybrid: CML178 x CML181.The mean plant height of the genotypes ranged from 51-136cm for the inbred parent CML177 and the hybrid, CML181 x CML176.Significant differences were observed among the genotypes, indicating that they were genetically distinct with regard to the genes controlling the expression of this character. Similarly ear height ranged from 13-53cm, indicating wide variability for this character among the genotypes. Days to maturity which is a baseline for selection of early maturing genotypes ranged from 67-109 days. The inbred parent CML493 had the lowest days to maturity (67-days). This indicates that this inbred parent can be included in cross combinations for selection of early maturity. Highly significant correlation was observed between ear height and plant height (p < 0.01). Similarly, days to silking and tasselling correlated positively and significantly at p < 0.05. Grain yield correlated positively and significantly with one thousand seed weight (p < 0.05). Number of leaves per plant had a significant positive correlation with ear height at p < 0.05, indicating that these traits could be selected together for simultaneous improvement. The phenotypic coefficients of variations were higher than the genotypic coefficients of variations for all the traits studied. Thousand seed weight had the highest genotypic coefficients of variation. The highest genetic gain was obtained for plant height. Thousand seed weight and ear height also recorded high genetic gain. It is anticipated that these findings will be useful in future breeding programmes involving this very important crop.